1. Field of the Invention
The present invention relates to a semiconductor device and a method for producing the same.
2. Description of the Related Art
Various packaging forms for semiconductor devices have been developed as technical progress relating to semiconductor integrated circuits has developed and demand for higher density packaging by increasing a number of pins has increased.
A prior art is described below with reference to FIGS. 13A and 13B. FIG. 13A is a schematic plan view showing a conventionally produced tape carrier. FIG. 13B is a cross sectional view taken along dashed line B-B in FIG. 13A.
In a conventional tape carrier, a number of device holes 114 are arranged in a series along a long axis direction of an elongated photographic-film-like base tape 140 made of a polyimide film, or the like. A plurality of carry holes 142 is provided in the vicinity of both short-axis-directional ends of the base tape 140 along the long axis direction of the base tape 140, and parallel to the device holes 114, in order to facilitate carrying, and the like, of the base tape 140 during production, transportation, and the like, thereof. A plurality of leads 120 is formed at each of the device holes 114.
As shown in FIG. 13B, each of the leads 120 is formed by providing a thin copper wire 120a with a metal plating 120b, which metal plating 120b is for a later bonding to a chip. Further, a solder resist 132 for protecting a wiring pattern is placed over portions of the leads 120 which are located on the base tape 140. Although it is not shown in the drawings, a chip is bonded to the leads 120 at a device hole side using metal eutectic bonding or thermo-compression bonding. Thereafter, molding is carried out to package the chip. Finally, the tape carrier is cut into respective frames and surface mounting onto printed wiring boards or the like is performed.
In comparison to other packaging forms, the above-described tape carrier packaging is easily made smaller and thinner and is extremely suitable for high-density surface mounting. Therefore, its range of usage is expected to continue to extended.
However, in the conventional tape carrier, a chip is supported only by the leads 120 to which it is bonded. Further, since the chip is supported in a slightly downward offset position with respect to the device hole of the carrier in order to prevent electrical short circuits in the wiring, namely, between the leads 120, defects such as deformation and breakage of the leads have been caused even by slight impacts occurring, for example, when the elongated tape carrier is wound, during transportation of the tape carrier, or even during quality inspection of the tape carrier. A fraction defective due to such defects has reached 5 to 10%. Thus, in order to improve a yield and with consideration of the difficulty of quality control, there is a demand for an immediate countermeasure.